Ultra high frequency resonator



Oct. 1950 H. J. M CARTHY ULTRA HIGH FREQUENCY RESONATOR Filed Jan. 11,1946- ////////&////

Henry J: 17 $1535! 9 Ian-m ATTORNEY Patented Oct. 3, 1950 ULTRA HIGHFREQUENCY RESONATOR Henry J. McCarthy, Danvers, Mass, assignor toSylvania Electric Products Inc., Salem, Mass., a corporation ofMassachusetts Application January 11, 1946, Serial No. 640,617

1 Claim.

This invention relates to ultra-high frequency resonators and the like,and particularly to such resonators used for response to a broad band offrequencies.

Broadening of the frequency band is obtained by coupling together two ormore resonators at a coefficient of coupling greater than the criticalvalue which produces sharp resonance.

In such devices it is necessary to tune all the resonators, and I havefound an adjustable screw entering the usual gap at the center of theresonator will provide the desired tuning. The screw at the center ofone of the resonators may be hollow, with a keep-alive electrode in it.

Further details, advantages and objects of the invention will beapparent from the following specification and its accompanying drawings.

Fig. l is a lateral cross-section of my device, taken through one of thesingle resonators accordin to my invention;

Fig. 2 is a longitudinal section through an assembly of three suchresonators in a wave-guide;

Fig. 3 is an external perspective view of the complete device.

InFig. l the resonator comprises the flat resonator disk I having thecut-out center portion 2 with the projection 3 and screw 4 extendinginto center portion 2 and having pointed portions 5 and 6 at theirrespective ends. These points should be accurately aligned. A bushing Iin the wave-guide 8 and resonator plate 1 forms a threaded seat for thescrew 4. A lock-nut 9 holds the screw in the position to which it isdesired to be set, and a slotted head I0 is provided for ease inadjustment. Once the adjustment is made, the lock-nut 9 and theexternally exposed part of the bushing 1 and screw 4 may be covered witha material suitable for vacuum sealing.

As in Fig. 2, there are preferably three resonator plates I, II, and 2|spaced apart in the rectangular wave-guide 8 a distance sufiicient toallow the desired coupling above the critical value. One of theresonator plates 2| may have a keepalive electrode 45 extending throughthe hollow screw 3i, which may be formed into a half-conical point 26 atits inner end. The keep alive wire 45 will then be led out through theglass tube 32, to which it is sealed.

The waveguide 8 has the windows 4| and 42 at each of its ends. A thinglass plate is sealed to each end to allow transmission of the wavestherethrough without allowing the gas inside the resonator to escape.The gas-filling may be, for example, hydrogen and Water vapor at a few mllimiters range Flanges 43 and 44 may be provided near each end of thewaveguide to facilitate attachment of the unit at its ends to otherwave-guides.

The glass tube 32, through which the keep alive 45 passes, is sealed tothe metal tube 46 which is held in communication with the interior ofhollow screw 3| by the collar 41, which may be of any suitable form. Thejoint may be soldered to provide a vacuum-tight seal. The screws 10, 3|,their locknuts 9, and the bushings I may also be soldered to thewaveguide I in a vacuum tight manner. The plates I, H, 2| may besoldered at their outside edges to the interior of the wave guide I.

What I claim is:

A resonator comprising: a metal waveguide having a longitudinal axis; aseries of metal plates in said waveguide transverse to its longitudinalaxis and spaced apart along said axis; each of said plates having acentral cut-out portion with a pointed reentrant projection; a pointedscrew extending from the outside of said waveguide into the cut-outregion of each of said plates opposite to and in register with saidpointed reentrant projection; a lock-nut for. each of said screws, oneof said screws being hollow having a pointed end and having an openingat that end; a metal tube attached to the end of said hollow screwoutside said waveguide; a glass tube sealed to the end of said metaltube; a keep alive electrode sealed through said glass tube andextending through the interior of said hollow screw to the openingtherein; a filling of gas at low pressure in said waveguide; and e,sealed window at each end of said waveguide to allow wave transmissiontherethrough; and means at each end of said waveguide for attachment toother waveguides.

HENRY J. MCCARTHY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS- Number Name Date 2,407,069 Fiske Sept. 3, 19462,408,055 Fiske Sept. 24, 1946 2,418,469 Hagstrum 1. Apr. 8, 19472,423,130 Tyrrell July 1, 1947 2,427,089 Clifford Sept. 9, 1947v2.46.2,093 Fox Dec. 9, 1947

